new guy here , need help with mcu communication.

[sssr1]

hello guys .

first , i want to say i'm sorry because i have a question about other brand mcu .if i cant do that , the mods can delete my thread , sorry again if this is the case.

also i want to say that i'm new to mcu's , be gentle

ok , the problem:

i bought a gauge cluster unit for my motorcycle .the unit i bought is from a different brand motorcycle , and it uses some type of serial data transfer between the gauges and the engine controll unit (ecu) for speed , temp  etc.

microcontroller inside is this one :

http://www.eu.necel.com/_pdf/U10335EJ2V0DS00.PDF

its 8 bit nec mcu.

i just wanted to know , is there a way to know what type of serial communication is used to transmit the data to this mcu? can it be full duplex communication also (which would complicate things even more)?

any help would be great.

[PeterHouse]

The NEC datasheet is of no benefit since it only describes the CPU and not how the designer configured or used it.

You will probably need an oscilloscope and probe the signals and determine what they are and how to work with them.  Full duplex is really no more difficult then half duplex at this point.

Are you planning on using a Freescale cpu to work with this gauge cluster?

Good Luck,

Peter

[sssr1]

i have a scope , but the problem is i dont have the ecu of that cluster gauge to see what kind of signal its sending.

when i hook the scope to the cluster itself , i get a low freq square wave with something like 99.8% duty cycle - the voltage stays at 12V and drops to 0 and back to 12V .it stays long at 12V...

i guess , without knowing the program inside that mcu ,there is no way to know what type of signal should be sent .

thatks for your reply anyway